Method of manufacturing dry, noncaking, readily-soluble soap in the form of threads



Patented Oct. 21, 1930 UNITED STATES PATENT OFFICE ADOLF WELTEB, OF KRLEFELD-RHEINHAFEN,' GERMANY METHOD OF MANUFACTURING DBY,'NO1\TGAKING, READILY-SOLUBLE SOAP IN THE FORM OF THREADS No Drawing. Application filed December 27, 1927, Serial No. 242,964, and in Germany December 20, 1926,

and ensure that this form is one in which the soap is very readily soluble. In this respect great advances have already been made by employing the atomizing process. There is a certain prejudice however in the trade against the powders obtained in this way as it is impossible for the general public to judge from the powder whether it is good or bad soap.

' The drying processes employed, in order to convert the soap as quickly as possible into a form ready for packing and use,-l1ave also been substantially improved by the continuously operating apparatus, but require a considerable amount of heat and time. Therefore any new method of converting liquid curd soap into a form ready for packing and despatch immediately without drying, is fundamentally an advance in the 'art. It has been 2 found however that the products hitherto obtained, which are placed on the'market mostly in the form of ribbons or-threads, do not satisfy the requirements with respect to rapid solubility, whichhave been in .demand since the introduction of the so-called soap flakes.

These soap flakes are not only products having an attractive appearance, but the user is able without any trouble to dissolve them rapidly even in cold water and thus reduce the time taken by washing. The manufacture of these flakes, particularly of very fine, glossy flakes obtained by rolling out soap free from water and cutting it on highly polished steel cylinders, is however very expensive, so that there can be no question of economy.

It has also been proposed by another inventor to force liquid soap by means of pumps through orifices having a large number of small perforations, of about mm. diameter. The emerging liquid soap is then supposed, owing to the large surface, to solidify and begin to dry under favourable conditions in the form of small filaments so rapidly that they no longer stick together when subsequently dried. This method is however inferior to the known atomizing process and does not result immediately in attractive and saleable products, but involves first of all intermediate products, which have to be further worked up. The method differs from all the methods subsequently described in that liquid soap is pumped through the apertures and only then solidifies and dries, whereas the other methods are more advantageous, because they employ as initial material soap already solidified which can then naturally no longer be pumpedv It has also been proposed by the inventor of the present method for the production of soap threads or strips, to add to liquid soap about a tenth of its weight of calcined soda or the like and to press the resulting viscous mixture into threads or strips.

, It has now been found according to the present invention that if solid soap is forced through nozzles having a diameter not exceeding about 1 mms., filaments are then obtained,iwhich do not cake together and dry or harden rapidly in such a way that they do not subsequently stick together and can be put into wrappersimmediately. The filaments then disintegrate within the course of a few hours into small glossy chips, imparting to the soap the appearance of small shining crystals and which are so readily soluble that they are not in any way inferior in this respect to the soap flakes. The surprising discoveryhas been made that by forcing solid soap through such fine nozzles even with a slight and unsubstantial pressure, a very large outputcan be obtained which is far more economical than the manufacture of soap flakes by rolling out.

A pressure of 5 to 25 atmospheres is fully sufficient, according to the combustion of the soap for forcing the dry soap through the 1 millimeter holes in the nozzle in order toforce the desired threads.

In my. invention I employ a solid soap as stated and by a solid soap I mean any of the ordinary soaps which have the appearance of being solid. I do not mean an absolutely dry soap but I do mean a soap which is some what plastic and which is the ordinary soap 'one obtains when making a purchase thereof. Such solid soaps contain water and the amount of water they contain is variable,

within wide limits. My invention essentially resides in the discovery that, when forcing such soaps through nozzles having a diameter not greater than 1 mm. I can obtain a product which is non-caking. I attribute this to the fineness of the soap threads initially produced. Large surface area is exposed and the soap threads dry almost at once. lVhen using nozzles or orifices of greater diameter, the soap threads have a tendency to cake together and this is the reason why prior proposals have not met with favor. It is only by using nozzles having a diameter not greater than 1 mm. that I am enabled to obtain non-caking threads and I regard this nozzle diameter as critical.

The economy is unfavourably affected by the addition of rosin; naturally the choice of the fats also plays an important art. It has been found that from soaps which hitherto were pressed into threads of 34 mm. diameter, and which then stuck together again and were thus unsaleable, it is possible when nozzles having a diameter of at most 1% mm. are used, to obtain filaments which no longer cake together after leaving the nozzle and are immediately ready to be put into wrappers, a production on a large scale being thereby rendered possible. In most cases it has been found that nozzles of 1 mm. are the extreme limit, at which these results can be obtained. 'On an average the best results are obtained when a nozzle orificeof 0.4 to 0.5 mm. is used. The threads met with in practice have on an average a diameter of 4 mm., but never less than 3 mm. The reason why such small dimensions have not hitherto been adopted is the comprehensible but incorrect assumption that in such a case a very great deal of power would be required and that the results would not be more favourable as far as the sticking together is concerned than with similar methods hitherto employed. The fact that even fine soap filaments, which were not produced by expressing but by scraping, still cake together, is evident from the fact that hitherto an attempt was then made to prevent the caking together by adding soda containing very little water or soap powder. An attempt was also made to roll soap out on suitable roller,

mills, and scrape it off by pointed or blunt needles, or cut it very fine by means of small blades and then scrape it 011' with scrapers in the form of small prisms of less than 1 mm. diameter. These products are also attractive and readily soluble, but are inferior in appearance to the filaments forced out of nozzles, especially as they seldom have a smooth surface. Moreover they cannot be produced so economically, as the rolling and scraping operations have to be preceded by an expensive drying process.

What I claim is 1. Inthe process of manufacturing noncaking, readily soluble soap in the form of threa s,- the step which comprises forcing solid soap through nozzles having a diameter not greater than 1 mm.

'2. A method of manufacturing dry, noncaking and readily soluble soap which comprises extruding solid soap under pressure through nozzles having a diameter not exceeding 1 mm. and allowing the soap threads so formed to break up into small shining crystal. a

In testimony whereof I have signed my name to this specification.

ADOLF WELTER. 

